Process of making sheet-metal doors, partitions and the like.



I. H. GRAVELL.

PROCESS OF MAKING SHEET METAL DOORS, PARTITIQNS, AND THE LIKE. APPLICATION FILED DEC. I6. I912.

1,156,898. Patented Oct. 19, 1915;v

"2 SHEETSSHEET I.

. WITNESSES INVENTOR JWW I M I "I z (6/ I Q ATTORNEYS v J. H. GRAVELL.

PROCESS OF MAKING SHEET METAL DOORS, PARTITIONS, AND THE LIKE.

APPLICATION FILED DEC. 16. 1912.

Patented 0013. 19, 1915.

2 $HEETS-SHEET 2 'WHIHWHIH INVENTOR WITNESSES ATTORNEY UNITED STATES PATENT OFFICE.

JAMES H. GRAVELL, OF PHILADELPHIA, PENNSYLVANIA, ASSIG-NOR '10 HALE'AND KILIBURN COMPANY, OF PHILADELPHIA, PENNSYLVANIA, A CORPORATION OF DELAWARE.

PROCESS OF MAKING SHEET-METAL DOORS, PARTITIONS, AND THE LIKE.

Specification of Letters Patent.

Patented Oct. 19, 1915.

Application filed December 16, 1912. Serial No. 736,908.

To all whom it may; concern:

Be it known that I, James II. (iRAVELL, a

citizen of the United States, residing'at' completed structure.

In the construction of sheet-metal doors and partitlons heretofore, it has been common to provide a pair of parallel sheet-metal pieces, shaped as may be desired, for the surface pieces of the door or partition and various metallicmembers of one form or another between these sheets and provided with projections or humps at intervals along their length, the said pieces and members being welded together when assembled in the proper relative positions at each of the projections or humps. I

The present invention relates to a process for making a structure of this type differing from those heretofore provided primarily in the construction of the metallic members which lie between and join the two surface sheets, the method employed in making the door also differing from previous methods largely because of the use of intermediate members of this different and novel form.

In accordance with the invention, the door consists of two metallicsheetsbetween which are arranged a plurality of thin, fiat, sheet- .metal strips, these strips being arranged parallel to each other and in planes trans verse to the planes ofthe surface sheets and having the surface sheets welded'to their opposite edges at a plurality of separated points along the strips. In order to fac1l1- tate the welding together of the surface sheets and intermediate strips, these strlps have projections or humps ralsed 1n the planes of the strips on opposite edges and at separated intervals along the length of. the strips. The projections along one of the edges of the strip are directly opposite those on the opposite edge, so that when oining the parts together the welding current may be passed through one surface sheet to a hump on the underlying strip and then through the hump on the opposite edge of the strip and the opposite'surface sheet, thus effecting two welds at one operation. The structure manufactured in accordance with this practice possesses the desirable characteristic of being very light in weight and, furthermore, it may be manufactured at a comparatively low cost, but these characteristics may be obtained without reduc-s tion in the strength of the completedstrue v ture. flhe strips between the two surface plates being arranged on edge, theirresistance to crushing of the door structure is very great.

I will describe the construction which I pre'ferto employ in the practice of my in-' vention, in connection with the accompany.- ing drawings, and will then point out certain advantageous features of this construction over the practice heretofore followed. I

In these drawings, Figure 1 is a diagrammatic view illustrating the. door structure and the method of making the same, Fig. 2 is a perspective view showing a plurality of intermediate strips and one form of support for holding them in their proper relative positions, Fig. 3 is a view similar to Fig. 2 but illustrating a slight modification, Fig. 4 is an elevation of one of the intermediate strips, Fig. 5 is a cross-section of the strip shown in Fig. 4, Fig. 6 is an elevation of a portion of a sheet-metal door, and Fig. 7 is a cross-section through a partially completed door structure.

Referring to these drawings, the door structure consists of'two sheet-metal plates 8 and 9 arranged parallel to each other and a plurality of sheet-metal strips 10, between the plates 8 and 9, parallel to each other and at right angles to the plates 8 and 9. These strips 10 act as spacers between the surface plates 8 and 9 and serve to connect those plates so as to form a rigid structure of great strength. The plates 8 and 9 may be given any shape desired for the surfaces of the door structure by pressing them into the desired form.

The strips are thin, flat, sheet-metal strips and they have aplurality of projec- I humps. The projection or hump 11 is raised by subjecting the strip 10 to blows on opposite sides thereof at a point adjacent to the edge of the strip. IV'hen the strip is subjected to such a blow, a depression is formed in the side of the strip adjacent to its edge,

as indicated at 12 in Fig. 5, and the metal at the edge ot' the strip is caused to flow to an extent sufficient to raise the projection 11 on the edge of the strip and in the plane there of. Strips of the character shown in'Figs. (l and 5 may be readily constructed at small expense by passing a sheet-metal strip of rectangular cross-sectidn through a punch press and operating the press so as to deliver a blow to opposite sides of. the strip adjacent to the edges of the strip at intervals along the length of the strip, thus spreading the metalat the point where the blow is delivered sufficiently to raise the projections 11.

In constructing a door employing strips of this character, a plurality of strips are arranged parallel one to another between two sheet-metal plates 8 and-9, the strips being disposed edgewise between the two plates, that is, in planes transverse to the planes of the plates. In order. to facilitate the assemblage of the parts in this manner and to hold the parts in proper relative positions during the welding operation, the several strips 10 employed in the door strucf ture may be provided with one or more support-ing devices extending between them and bracing them one on another. In Fig. 2', a plurality of parallel. strips 10 are shown having a support 13 extending between them and secured thereto. This support 13 is a thin, flat, sheet-metal strip and extends across and is welded to all of the strips to be employed in the door structure. In Fig. 3, a different-form of support is shown. In this case each of the strips 10 is slotted and a sheet-metal strip lis provided with slots spaced apart a distance corresponding to the distance between adjacent strips 10,.the

strips 10 and 14 being assembled as is shown in the drawings, so that the support 14: will hold the strips 10 in their parallel relationand at proper distances apart, even though it is not welded thereto. l

When a plurality of the strips 10 have been assembled edgewise between the two plates 8 and 9, these parts are secured to-- gether by welding the plates 8 and 9 to Such a machine is indicated diagrammatr cally in Fig. 1, wherein 15 is the core of a transformer, 16 the primary coil thereof and 17 the secondary coil. The secondary is provided with terminals 18 between which the parts to be welded are inserted. Suitable means are provided for forcing the terminal 18 together against the parts to be welded, but this is not shown in the drawings, as it is a provision common to all welding machines. Vhen the parts of the door are in proper position between the terminals of the welding machine, these terminals are forced against the plates 8 and 9 and the circuit of the welding current is closed. The humps or projections on the strips 10 confine the current to a relatively small area in its passage through the strips 10 and the projections 11 are rapidly reduced so that a weld is made between the strip 10 and each of the outside plates. As the projection 11 is reduced, the plates 8 and 9 are'forced together so that at the end of the welding operation these plates li'ein contact with the edges of the strips 10 between the welds.

In the manufacture of structures of the character herein shown, it has been common heretofore to employ sheet-metal strips bent to a channel form between the two outside plates, these channel strips being provided with projections or humps at separated points along their length adapted to contact I sacri ce in the strength of the structure is made by the employment of the flat strips rather than channel-shaped strips, as the flat strip possesses ample strength in resisting crushing strains. When intermediatestrips of channel shape are employed, the sides of the channel strips are apt to yield toward each other during the we ding operation, unless means are provided for guarding against this, and if such yielding took- For this reason, it has been proposed to employ place the welds might be imperfect.

a mandrel in connection with such a channel-shaped strip by inserting this mandrel within the strip to sustain the opposite sides of the strip during the welding operationand withdrawing the mandrel after the welds have been effected. Employing a mandrel in this way adds to the cost of production of the structure and is objectionable 5 for this reason, but in addition to this it frequently happens that the use of a mandrel in this manner is impossible In some cases, the plates for the sheet-metal structure are so shaped that the distance between them is greater at an intermediate point than it is at I points adjacent to the edges of the plates. For instance, a sheet-metal door might have the side plates therefor pressed to such form that a panel extending over a large area near the center line of the door would be of greater thickness than a portion extending around the panel. In the manufacture of such a structure, it would be impossible 'touse a mandrel which is to be withdrawn 9 after the completion of the welding operation. In'many cases, a sheet-metal structure is such that the edges thereof must be closed before the welds over the surface thereof V have been made, and imsuch'cases it is impossible to employ within the door a part which must be removed after the welding 7 operation. Here, again, a mandrel for sup porting opposite sides of a sheet-metal Chan-.-

nel lying between the side plates could not be employed. In all instances of this character the. construction shown in the drawings and above described may be employed,

and the value of this construetion is increased by the Wide range of its utility. Having described my invention, what I claim as new therein and desire to secure by Letters Patent of the United States is:

1. The process of making a sheet-metal door, partition or the like, consisting in arranging a plurality of thin flat metal strips 40 in definite relation to each other on edge, said strips haying raised projections at spaced intervals along their edges, supporting said strips in such relation by a supporting member transverse thereto, placing the strips thus arranged between two parallel sheet-metal plates with each strip disposed in a plane transverse to the planes of said plates, and then welding each of said plates to each of said strips through said raised projections, substantially as set forth. 2. The process of, making a sheet-metal door, partition or the like, consisting in arranging a plurality of thin flat metal strips in definite relation to each other on edge, said strips having raised projections at spaced. intervals along their edges, support ng said strips in such relation by asupporting member transverse thereto, said strips being secured together by a mortised connection with said member, so arranged that no surface of said member projects beyond an edge plane of said strips, placing the strips thus arranged between two parallel sheet-metal plates with eac'h'strip disposed in a plane transverse to the planes of said plates, and then welding each of said plates-to each of saidstrips through said raised projections, substantially as set forth.

This specification signed and witnessed this 11th day of December, 1912.

JAMES H. GRAVELL. 

